Each of electronic devices, which has become necessities of modern people due to ease in carrying it, has been developed into each of multimedia devices which provides various services such as a voice and video communication service, an information input and output service, and a data transmission and reception service.
Recently, as copy and transmission technologies of the electronic devices have been sharply developed, a problem of an illegal copy of digital contents has been resurfaced.
In order to protect a copyright of digital data, there is a digital watermarking technology for inserting secret information such as copyright information into various digital data such as images or videos. That is, original source and information of digital data may be tracked by inserting pictures or texts into the digital data.
Therefore, it is needed to provide a method and apparatus for matching a watermark inserted into digital data with an original watermark to extract the watermark inserted into the digital data and certify ownership of the digital data.